Changed the Low Pass Filter algorithm. The new one is faster and closer to Creative labs SoundBlaster implementation. This filter has only one slope, so the slope parameter has been removed.

The shape of the Modulation Envelope Attack phase has changed: instead of linear it is now concave with a very steep initial rise. This is close to the SoundBlaster implementation. Also some other Modulation Envelope features have been tuned.

The SoundFont history list now only displays the SoundFont file name and not the whole path.

Bug fixes in version 1.633:

Sometimes you could not select a track in the tracks list as another one "got stuck" (since 1.630).

The presets list in the SoundFont file open dialog did not show percussions (since 1.630).